Say we use clang-format now

.github/CONTRIBUTING.md

@@ -65,17 +65,19 @@ request, please ensure that:
 To send us a pull request, please:
 
 1. Fork the repository.
-2. Modify the source; focus on the specific change you are contributing. If you
-   also reformat all the code, it will be hard for us to focus on your change.
-3. Follow the
-   [coding style guide](https://www.freertos.org/FreeRTOS-Coding-Standard-and-Style-Guide.html).
-4. Commit to your fork using clear commit messages.
-5. Send us a pull request, answering any default questions in the pull request
-   interface. NOTE: Please make sure the default option (Allow edits from
-   maintainers) is left checked.
-6. Pay attention to any automated CI failures reported in the pull request, and
+1. Modify the source; please focus on the specific change you are contributing.
+   If you also reformat all the code, it will be hard for us to focus on your
+   change.
+1. Ensure that your contributions conform to the
+   [style guide](https://www.freertos.org/FreeRTOS-Coding-Standard-and-Style-Guide.html).
+1. Format your code with `clang-format`, using the config available at
+   [.clang-format](../.clang-format).
+1. Ensure local tests pass.
+1. Commit to your fork using clear commit messages.
+1. Send us a pull request, answering any default questions in the pull request
+   interface.
+1. Pay attention to any automated CI failures reported in the pull request, and
    stay involved in the conversation.
-
 GitHub provides additional document on
 [forking a repository](https://help.github.com/articles/fork-a-repo/) and
 [creating a pull request](https://help.github.com/articles/creating-a-pull-request/).